# CVE-2022-49810: netfs: Fix missing xas_retry() calls in xarray iteration

CVE-2022-49810 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-49810, released May 1, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-49810
- Priority: Routine
- CVSS: 5.5 (Moderate)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 1, 2025
- Weakness: NULL Pointer Dereference
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-49810

## Description

In the Linux kernel, the following vulnerability has been resolved:  netfs: Fix missing xas_retry() calls in xarray iteration  netfslib has a number of places in which it performs iteration of an xarray whilst being under the RCU read lock.  It *should* call xas_retry() as the first thing inside of the loop and do "continue" if it returns true in case the xarray walker passed out a special value indicating that the walk needs to be redone from the root[*].  Fix this by adding the missing retry checks.  [*] I wonder if this should be done inside xas_find(), xas_next_node() and     suchlike, but I'm told that's not an simple change to effect.  This can cause an oops like that below.  Note the faulting address - this is an internal value (|0x2) returned from xarray.  BUG: kernel NULL pointer dereference, address: 0000000000000402 ... RIP: 0010:netfs_rreq_unlock+0xef/0x380 [netfs] ... Call Trace:  netfs_rreq_assess+0xa6/0x240 [netfs]  netfs_readpage+0x173/0x3b0 [netfs]  ? init_wait_var_entry+0x50/0x50  filemap_read_page+0x33/0xf0  filemap_get_pages+0x2f2/0x3f0  filemap_read+0xaa/0x320  ? do_filp_open+0xb2/0x150  ? rmqueue+0x3be/0xe10  ceph_read_iter+0x1fe/0x680 [ceph]  ? new_sync_read+0x115/0x1a0  new_sync_read+0x115/0x1a0  vfs_read+0xf3/0x180  ksys_read+0x5f/0xe0  do_syscall_64+0x38/0x90  entry_SYSCALL_64_after_hwframe+0x44/0xae  Changes: ======== ver #2)  - Changed an unsigned int to a size_t to reduce the likelihood of an    overflow as per Willy's suggestion.  - Added an additional patch to fix the maths.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.0.10-1 | [DEBIAN-CVE-2022-49810](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49810.md) | May 1, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.0.10-1 | [DEBIAN-CVE-2022-49810](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49810.md) | May 1, 2025 |
| Linux | linux Debian 14 | 6.0.10-1 | [DEBIAN-CVE-2022-49810](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49810.md) | May 1, 2025 |

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